Double expansion ball float gas system for a firearm



10, 1959 D. L. KATz ,872,851

DOUBLE EXPANSION BALL FLOAT GAS SYSTEM FOR A FIREARM Filed May 16, 1957 Fig-3- Fig-4- INVENTOR. D uvi 11 L K 1112.

United States PatentU DOUBLE EXPANSION BALL FLOAT GAS SYSTEM FOR A FIREARM David L. Katz, Springfield, Mass assignor to theUnited States of America as represented by the Secretary of the Army Application .May 16, 1957, Serial No. 659,738

lClairn. (c1. 89-.---193) (Grantedunder Title 35, U. S. Code (1952), see. 266) I The invention described herein may be manufactured and "used'by or for the Government for governmental purposes without the, payment of any royalty thereon.

Thisinvention relates to firearms ,andmore particularly to gas-operated actuating mechanismstherefor, i v It] is an object of this inventionto providerfor firearms a gas-operated actuating mechanism which is espe- 7 here has dropped below that in the chamber.

The specificnature of the invention as well as other objects and advantages thereof will clearly appear from a description of a preferred embodiment as shown in the accompanying drawing in which:

Fig. l is a partially cross-sectional side view of the gas system showing the parts in normal position;

Fig. 2 is a view similar to Fig. l but showing the relationship of the parts after the projectile of a cartridge discharged in the barrel has passed the gas port leading from the barrel bore to the gas system;

Fig. 3 is a view similar to Figs. 1 and 2 but showing the relationship of the parts when the pressure in the chamber is greater than that in the bore of the barrel; and

Fig. 4 is a fragmentary top view with the screw, plug, ball and sphere removed.

Shown in the figures is a firearm barrel 12 provided with a bore 14 and a gas system 16 which is mounted to the barrel by means of a bracket 18. Gas system 16 includes a cylindrical housing 20 which is centrally received by a collar portion 22 on bracket 18 and a countersunk bore 24 in the bracket aligns with a radial port 26 in barrel 12 to provide communication between bore 14 and such housing. Port 26 is positioned in barrel 12 so as to bleed gases from bore 14 where the gas pressure from a discharged cartridge reaches its peak, which is determined by the time displacement curve of such ammunition. Provided in the rear portion of housing 20 is a longitudinally disposed cylinder 28 which slidingly receives a piston 39. Vents 32 are provided through cylinder 28 for exhausting the gases therefrom when piston 30 is in a rearward position.

Provided in the front portion of housing 20 is a chamber 34 which communicates with cylinder 28 by means of a bored passageway 36. A cylindrical well 38 terminated by a semipherical portion 41 extends from here 24 to join with passageway 36 and form at such junction 2. pair of diametrically-opposed orifices 42 which are closable by a ball 44 which has a diameter similar to well 38 so as to be slidingly received thereby. The outer portion of well v38 is counterbored, as noted at 46, and

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is threaded to receive a screw 48 for limiting themo'vement of ball 44 in well 38 and inclosing'the top of such well. An aperture 50 having a diameter smaller than well 38 extends axially-through screw 48 whereby ball is actuatable against semispherical portion 40 to close the orifices 42 by the pressure of the gases in bore 14.

Extendingforwardly from well 38 immediately below counterbore portion is abore52'which communicates with chamber 34. A well 54 extends downwardlyfrom the top of housing 20' above bore 52 and an elongated, semicylindrical channel 58 extends down from well 54 to j'oin the; bore and fortnat each end of; the channel a'spherically formed terminating wall'having'a mouth 60 which provides communication "between such bore and channel.

The front portion of-bore 52'is, cut away along the underside thereof to form a semicircular wall 62' disposed midway of channel 58 and an elliptical portion 6i by which the front one of the mouths 60 is enlarged to extend rearwardly along the bottom of such channel to such wall, as" noted at 66. A sphere68'having a radius similar to that of channel58- is slidingly received thereby so as to block the rear one 'of the mouths 66 when in rearward position but leaves extended portion 66 of the front one of the mouths 60 open when in forward position.

The top portion of well 54 is counterbored, as noted at 70, to form an annular shoulder 72 and threadably received by such counterbored portion and well is a plug 74 having a stern portion 76 receivable by such well, a body portion 78 threada-bly received by counterbored portion 70 and an annular ledge 80 contactable with shoulder 72 to establish the assembled position of the plug. Provided in the bottom of stem portion 76 is a cylindrical recess 82 which extends upwardly to a circular planar portion 84 which slidingly engages sphere 68 to retain such sphere in channel 53 with a minimum of tolerance therebetween so that 'such sphere blocks the front one of the mouths 60 when gas pressure is exerted against such sphere-from chamber 34.

Thus, when a cartridge is fired in barrel 12 and a projectile therefrom moves along bore 14, the gases from the discharge enter port 26 after the projectile passes thereby and proceeds along bore 24 and aperture 50 into well 38. The pressure of the gases in well 38 presses ball 44 against semispherical portion 40 to block the orifices 42. But the gases are free to pass into chamber 34 as the gases in bore 52 move sphere 68 to the front end of channel 58 and so unblock mouth extension 66 permitting the gases to enter into chamber 34.

As long as the gas pressure in bore 14 is greater than that in chamber 34, such chamber will continue to receive the gases thereinto. However, when the pressure in bore 14 drops below that in chamber 34', the movement of the gases in bore 52 will be reversed and there- 'by sphere 68 is moved to the rear end of channel 58 to block the rear one of the mouths 6t) and prevent the escape of any gases thereby to bore 14. At the same time, the pressure of the gases in chamber 34 moves rearwardly along passageway 36 and through the front one of the orifices 42 beneath ball 44, which is raised thereby to unblock the orifices, permitting the gases to flow from chamber 34 into gas cylinder 28 to actuate piston 30 rearwardly. When piston 30 reaches rearward position, the vents 32 are uncovered permitting the gases in'the system to escape to the atmosphere, and a suitable spring (not shown) returns the piston to normal forward position.

From the foregoing, it is clearly apparent that there is herein provided a simple and rugged gas systemhaving only two balls as moving parts. It is also evident that the gas system is especially well adapted for use with firearms utilizing cartridges which produce a low gas pressure of short duration as the gases are bled from the bore to the chamber for storage therein when at their peak and are not released for operating the actuating mechanism until the pressure in the bore has receded.

Although a particular embodiment of'the invention has been described in detail herein, it is evident that many variations may be devised within the spirit and scope thereof and the following claim is intended to include such variations. 7

I claim: V I p In a firearm having a barrel with a radially-disposed port for bleeding gases therefrom, a housing mounted to the barrel and including a cylinder with a cooperating piston, a chamber for storing gases, a passageway to provide communication between said cylinder and said chamber, a cylindrical well for receiving gases bled through the port, a semispherical portion terminating from said well and disposed to interrupt said passageway, a pair of diametrically opposed orifices formed by the junction of said semispherical portion with said passageway, a -ball movably disposed in said well and said semispherical portion to releasably block said orifices and said passageway through the pressure of the gases bled from the barrel when greater than that of the gases in said chamher, a bore extending from said well through an elliptical opening extending therefrom to said chamber, a sphere, an elongated channel intersecting said bore and said elliptical opening and' disposed to rollingly receive said sphere for reciprocation between the front and rear ends of said channel, a front mouth formed by the intersection of said channel with said elliptical opening and disposed to pass gases from the barrel into said chamber past said sphere when the pressure of the gases in the barrel is greater than that in said chamber and said sphere is moved against said front mouth by the greater gas pressure in the barrel, and a rear mouth formed at the rear end of said channel by the intersection of said channel with said bore and disposed for cooperation with said sphere to block said bore when the gas pressure in said chamber is greater than that in the barrel.

References Cited in the'file of this patent UNITED STATES PATENTS 2,149,512 Eiane Mar. 7, 1939 FOREIGN PATENTS 31,655 Austria Feb. 10, 1908 31,656 5 Austria 'Feb. 10, 1908 597,634 Germany Mar. 28, 1934 

